Electric signaling device



Sept. 19, 1933. L. J. LOEFFLER ELECTRIC SIGNALING DEVICE Filed May 21, 1930 Fig.2,

L INVENTOR BY ouzs I loe lfzer TORNEYS Patented Sept. 19, 1933 t ELECTRIC SIGNALING DEVICE Louis J. Loeffler, Stapleton, N. Y. Application May 21, 1930. Serial No. 454,294

2 Claims.

This invention relates essentially to an electric signaling device of that type in which a diaphragm made of thin resilient steel is caused to vibrate by energizing a magnet arranged in a metal box.

An object of the invention is to clamp the diaphragm between side flanges of the box and ribs I on the cover so that almost its entire area is free to vibrate.

Another object of the invention is to mount the electromagnet on a spring plate fixed in the box whereby it can be adjusted to vary its proximity to the magnet.

The invention resides more particularly in the novel combinations described and claimed in the following specification, reference being had to the accompanying drawing, in which:

Fig. 1 represents a vertical section of a device embodying this invention.

Fig. 2 is a plan view of the cover and diaphragm removed.

Fig. 3 is a plan View of the diaphragm.

Fig. 4 is an inverted plan view of the cover.

In the drawing the numeral 5 designates a box which is made of sheet metal andthe upper end of each side wall is bent at right angle to form a pair of flanges 6 extending the width of the box. On the flanges is supported a resilient diaphragm 7 made of silicon steel and having cut out portions 8 at the front and rear as indicated in Fig. 3 to reduce its area thus giving greater resiliency beyond its support. A cover 9 arranged over the diaphragm is adapted to close the box. The cover is provided with downwardly projecting lugs 10 on each side to engage under the flanges and it has a transverse rib 11 on each side adjacentthe lugs to contact with the margins of the diaphragm. This arrangement clamps the cover to the box and securely fastens the diaphragm. The upper end of the box at the front and rear is partly cut away as shown at 12 to permit downward play room of the diaphragm. The cover has a horn oramplifying device 1% projecting upward to increase the sound volume.

The box is practically rectangular and a spring steel plate 15 having an upwardly turned end is fastened by means of bolts 16 to the inner side of the box. The body of the plate normally rests on the bottom of the box and the forward part is turned upward at 17 to function as an inclined plane. A set screw 18 is threaded in the side of the box and its stem impinges on the upturned end of the plate.

A bobbin or electromagnet 19 is positioned on the plate and it has a coil of wire 20 wound thereon with terminals 21 connected to an alternating current source of electric energy. The bobbin is provided with a soft iron core or pole member 22 secured at its lower end to the plate and a key 24 forced in a slot in'its upper end 6 fastens the bobbin to the core.

It should be noted that the diaphragm is fastened between the flange and the rib at both its ends thereby leaving the greater portion beyond the ribs free to vibrate. When it is desired to adjust the electromagnet relative to the diaphragm the screw 18 is actuated, which in conjunction with the inclined plane flexes the plate and moves the magnet toward or away from the diaphragm. When the electromagnet is energized by means of an alternating current it causes the diaphragm to strike against the pole member and to spring back to its normal position in rapid succession thus producing a buzzing or humming sound which is intensified by the amplifier.

I claim:

1. As an article of manufacture an electric signaling device comprising a rectangular open-end sheet metal box having an outwardly bent flange on two of its opposite walls at the open end of the box, a diaphragm of a shape adapted to cover the open end of the box and the flanges, the diaphragm having cut-out portions on the edges which are adapted'to lie adjacent the unflanged walls of the box, a magnet having a core with an end adjacent the plane of the open end of the box, means for securing the magnet to the box, a cover shaped to overlie the diaphragm and box and interengaging means on the cover and box for securing the two together with the diaphragm between them, and means for bringing electrical connections from the magnet through the box walls.

2. An article of manufacture as in claim 1 in which the mounting means for the magnet includes a spring member having one end bent at right angles to the main portion of the member, and secured to a side wall with the main portion substantially parallel to the end wall, the other end being curved away from said wall and a set screw in the box wall opposite that to which the spring member is secured and bearing against the curved portion of the spring member.

LOUIS J. LOEFFLER. 

